Jake Butt only needs to go to his smartphone to find motivation for the future.

Never mind that the former Michigan tight end is going through rehabilitation after undergoing reconstructive ACL surgery for the second time in three years.

Never mind that he’s at the 2017 NFL Combine this week in Indianapolis, looking for job prospects in professional football.

Playing in the NFL, he said Friday afternoon at Lucas Oil Stadium, has been a lifelong dream.

But he also knows plenty have doubted him. Sustaining an ACL tear in his right knee on Dec. 30 when Michigan faced Florida State in the Orange Bowl may have added to those doubts — for everyone except Butt.

“I’ve kind of built my career on people doubting me,” Butt said. “I came in from high school, a skinny kid, and a lot of people didn’t expect me to have the career I had at Michigan. Now there’s people out here who don’t even expect me to ever play in the NFL.

“Knowing the type of competitor I am, I save those tweets. I’ve got them screen-shotted and stowed away. If I ever get tired, I guarantee I’ll be doing a couple extra reps for those people.”

Butt said he underwent surgery Jan. 10 and mapped out rehabilitation: running three months after surgery, doing cutting drills about 4 1/2 months after surgery and participating in football drills 5 1/2 months after surgery, with medical clearance six months after surgery.

Butt told reporters that he is not doing physical testing at the combine and that he didn’t anticipate doing much in private workouts for teams. Instead, he will focus on the value of rehabilitation in preparation for professional football, and also focus on the value of face-to-face meetings with NFL team personnel.

“It’s more just getting to know the coaches and the organizations, and them checking in on how my rehab’s going, what kind of guy I am and my love for the game, and getting to know me as a person,” Butt said.